Mucinous Adenocarcinoma of the Salivary Gland: A Review of a Rare Tumor

Objective To describe the clinical, demographic, and prognostic features of salivary gland mucinous adenocarcinoma, a rare head and neck malignancy. Study Design Population-based national cancer registry analysis. Setting Academic medical center. Subjects and Methods A review was performed with the National Cancer Database from 1998 to 2012. Demographic, clinical, and survival characteristics were compiled and analyzed. Cox multivariate regression was used to identify predictors of survival. Log-rank tests were used to test survival differences unless otherwise specified. Results A total of 170 cases were identified. The most common site of involvement was the parotid gland. Rates of nodal and distant metastases were 45.9% and 10.6%, respectively. High histologic grade was associated with nodal disease (P < .001) and advanced-stage disease (P = .006). Overall 5- and 10-year survival rates were 60% and 44%, respectively. Multivariate analysis found tumor size 2 cm (hazard ratio, 22.6; 95% confidence interval: 4.06-126.09; P < .001) and distant metastases (hazard ratio, 17.6; 95% confidence interval: 3.75-82.68; P < .001) to predict poor outcomes. Conclusions Mucinous adenocarcinoma of the salivary gland is a rare otolaryngic cancer. Regional metastases and advanced stage are more common with high histologic grade. Tumor size and distant metastases negatively influence survival.